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<head><meta charset="utf-8"><title>weekly meeting 2019-09-12 #54818 · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html">weekly meeting 2019-09-12 #54818</a></h3>

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<a name="175517937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175517937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175517937">(Sep 12 2019 at 10:59)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span> ; the triage meeting will be starting in about 3 hours</p>



<a name="175517960"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175517960" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175517960">(Sep 12 2019 at 10:59)</a>:</h4>
<p>I will be doing <a href="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-09-12.20.2354818/near/175517941" title="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-09-12.20.2354818/near/175517941">pre-triage in a parallel topic</a></p>



<a name="175518033"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175518033" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175518033">(Sep 12 2019 at 11:00)</a>:</h4>
<p>According to the current <a href="https://rust-lang.github.io/compiler-team/about/triage-meeting/#working-group-check-in" target="_blank" title="https://rust-lang.github.io/compiler-team/about/triage-meeting/#working-group-check-in">WG checkin schedule</a>, we are supposed to hear from <a href="https://rust-lang.github.io/compiler-team/working-groups/polonius/" target="_blank" title="https://rust-lang.github.io/compiler-team/working-groups/polonius/">WG Polonius</a> and <a href="https://rust-lang.github.io/compiler-team/working-groups/rfc-2229/" target="_blank" title="https://rust-lang.github.io/compiler-team/working-groups/rfc-2229/">WG RFC 2229</a> this week</p>



<a name="175518133"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175518133" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175518133">(Sep 12 2019 at 11:02)</a>:</h4>
<p>(i'm digging this "new" <a href="http://rust-lang.github.io/compiler-team" target="_blank" title="http://rust-lang.github.io/compiler-team">rust-lang.github.io/compiler-team</a> site that has arisen in my absence, by the way. Good job to everyone who has been working on that.)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175518188" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175518188">(Sep 12 2019 at 11:03)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>  will you have anything to report regarding the above two WG's? (I'll also ping <span class="user-mention" data-user-id="128294">@blitzerr</span> in case they would like to present on behalf of WG RFC 2229)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175519678" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175519678">(Sep 12 2019 at 11:29)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span>  unfortunately, I won't be available then. I would let Niko take it over.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175522403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175522403">(Sep 12 2019 at 12:11)</a>:</h4>
<p><span aria-label="exclamation" class="emoji emoji-2757" role="img" title="exclamation">:exclamation:</span> lets make sure we look at nominated issue "Make the generator-locals debuginfo test resilient to re-ordering." <a href="https://github.com/rust-lang/rust/issues/63742" target="_blank" title="https://github.com/rust-lang/rust/issues/63742">#63742</a> today (at request of <span class="user-mention" data-user-id="124287">@mw</span> , who will unfortunately be absent from the meeting itself.)</p>



<a name="175522995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175522995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175522995">(Sep 12 2019 at 12:19)</a>:</h4>
<p>I can prep a short report on both wgs</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523249" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523249">(Sep 12 2019 at 12:23)</a>:</h4>
<blockquote>
<p><span aria-label="exclamation" class="emoji emoji-2757" role="img" title="exclamation">:exclamation:</span> lets make sure we look at nominated issue "Make the generator-locals debuginfo test resilient to re-ordering." <a href="https://github.com/rust-lang/rust/issues/63742" target="_blank" title="https://github.com/rust-lang/rust/issues/63742">#63742</a> today (at request of <span class="user-mention silent" data-user-id="124287">mw</span> , who will unfortunately be absent from the meeting itself.)</p>
</blockquote>
<p>hmm I see why <span class="user-mention" data-user-id="124287">@mw</span> was concerned; not sure why we didn't discuss this earlier, I think I somehow failed to understand the concern. It'd be good if <span class="user-mention" data-user-id="116883">@tmandry</span> were able to dig into it more deeply. </p>
<p>Or perhaps <span class="user-mention" data-user-id="119009">@eddyb</span> could take a look? My hunch is that this is something related to debuginfo.</p>
<p>I guess the hypothesis is that LLVM is re-ordering some writes without realizing that those reorders are visible to debuginfo?</p>
<p>Put another way: we have no evidence that these "intermediate states" are visible to Rust code outside of a debugger, right? If so, it seems like a bug, but not a stability concern.</p>



<a name="175523391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523391">(Sep 12 2019 at 12:25)</a>:</h4>
<p>given what @vext01 aka <span class="user-mention" data-user-id="223288">@Edd Barrett</span> has been doing... it wouldn't surprise me if that's a bug in their MIR pass</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523451" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523451">(Sep 12 2019 at 12:26)</a>:</h4>
<p>I agree with <span class="user-mention" data-user-id="124287">@mw</span>, this is debuginfo test, it shouldn't be optimizing anything</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523457">(Sep 12 2019 at 12:26)</a>:</h4>
<p>Yep, I mostly wanted to make sure the folks working on generators take a look at this.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523463">(Sep 12 2019 at 12:26)</a>:</h4>
<p>pretty much everything would show &lt;optimized out&gt; in a debugger if we did enable optimizations</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523595">(Sep 12 2019 at 12:28)</a>:</h4>
<p><span class="user-mention" data-user-id="124287">@mw</span> some context: <span class="user-mention" data-user-id="223288">@Edd Barrett</span> is working on some tracing-JIT type stuff, not that different from holyJIT IIRC</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523638" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523638">(Sep 12 2019 at 12:29)</a>:</h4>
<p>I doubt what they're observing can be triggered without their pass because I doubt LLVM does anything to this code</p>



<a name="175523736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175523736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175523736">(Sep 12 2019 at 12:30)</a>:</h4>
<p>also, LLVM likely doesn't even have enough information to know that the generator state isn't aliased, so it's likely writes to the variable in question can't even be optimized by LLVM even if optimizations were enabled (cc <span class="user-mention" data-user-id="116883">@tmandry</span>) <strong>EDIT</strong>: okay it could just inline everything first</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175524326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175524326">(Sep 12 2019 at 12:38)</a>:</h4>
<p><span aria-label="exclamation" class="emoji emoji-2757" role="img" title="exclamation">:exclamation:</span> anyone here have access to an arm/musl system? This is regarding P-high: "Stable rustc always panics on arm/musl" <a href="https://github.com/rust-lang/rust/issues/60297" target="_blank" title="https://github.com/rust-lang/rust/issues/60297">#60297</a></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175524631" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edd Barrett <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175524631">(Sep 12 2019 at 12:43)</a>:</h4>
<blockquote>
<p>given what @vext01 aka <span class="user-mention silent" data-user-id="223288">Edd Barrett</span> has been doing... it wouldn't surprise me if that's a bug in their MIR pass</p>
</blockquote>
<p>This is entirely possible.</p>
<p>FWIW, here's the pass:<br>
<a href="https://github.com/softdevteam/ykrustc/blob/master/src/librustc_mir/transform/add_yk_swt_calls.rs" target="_blank" title="https://github.com/softdevteam/ykrustc/blob/master/src/librustc_mir/transform/add_yk_swt_calls.rs">https://github.com/softdevteam/ykrustc/blob/master/src/librustc_mir/transform/add_yk_swt_calls.rs</a></p>



<a name="175524770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175524770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175524770">(Sep 12 2019 at 12:45)</a>:</h4>
<p>(deleted)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175524789" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175524789">(Sep 12 2019 at 12:45)</a>:</h4>
<p>(deleted)</p>



<a name="175525081"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175525081" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175525081">(Sep 12 2019 at 12:49)</a>:</h4>
<p><span class="user-mention" data-user-id="223288">@Edd Barrett</span> does your pass run before or after the generator transform pass? can you move it to be just before/after (the opposite of what it was) and try that test again?</p>



<a name="175525322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175525322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edd Barrett <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175525322">(Sep 12 2019 at 12:52)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="223288">Edd Barrett</span> does your pass run before or after the generator transform pass? can you move it to be just before/after (the opposite of what it was) and try that test again?</p>
</blockquote>
<p>It runs as the last pass (besides dumping MIR):<br>
<a href="https://github.com/softdevteam/ykrustc/blob/bf7c6f32c1c4d520213f8236582c53ec7f2887ee/src/librustc_mir/transform/mod.rs#L292" target="_blank" title="https://github.com/softdevteam/ykrustc/blob/bf7c6f32c1c4d520213f8236582c53ec7f2887ee/src/librustc_mir/transform/mod.rs#L292">https://github.com/softdevteam/ykrustc/blob/bf7c6f32c1c4d520213f8236582c53ec7f2887ee/src/librustc_mir/transform/mod.rs#L292</a></p>
<p>We kind of need to it be there, but I can try moving it temporarily if it helps with diagnosis.</p>



<a name="175526213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175526213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175526213">(Sep 12 2019 at 13:02)</a>:</h4>
<blockquote>
<p><span aria-label="exclamation" class="emoji emoji-2757" role="img" title="exclamation">:exclamation:</span> anyone here have access to an arm/musl system? This is regarding P-high: "Stable rustc always panics on arm/musl" <a href="https://github.com/rust-lang/rust/issues/60297" target="_blank" title="https://github.com/rust-lang/rust/issues/60297">#60297</a></p>
</blockquote>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> yeah that feels like one that <em>should</em> be good to draw attention to outside of this meeting. That's been on my list forever.</p>



<a name="175526227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175526227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175526227">(Sep 12 2019 at 13:02)</a>:</h4>
<p>Honestly maybe just tweeting about it.</p>



<a name="175526230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175526230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175526230">(Sep 12 2019 at 13:03)</a>:</h4>
<p>I can just do that right now.</p>



<a name="175526443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175526443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175526443">(Sep 12 2019 at 13:04)</a>:</h4>
<p><a href="https://twitter.com/nikomatsakis/status/1172133974715637765" target="_blank" title="https://twitter.com/nikomatsakis/status/1172133974715637765">https://twitter.com/nikomatsakis/status/1172133974715637765</a></p>
<div class="inline-preview-twitter"><div class="twitter-tweet"><a href="https://twitter.com/nikomatsakis/status/1172133974715637765" target="_blank"><img class="twitter-avatar" src="https://pbs.twimg.com/profile_images/1110539492706914304/NUeyOrLX_normal.png"></a><p>Anybody out there using ARM with the MUSL version of libc? Interested in contributing to #rustlang? Maybe see if you can figure out why arm/musl seems to panic immediately: <a href="https://t.co/K6VEWcqkRc" target="_blank" title="https://t.co/K6VEWcqkRc">https://github.com/rust-lang/rust/issues/60297</a></p><span>- Niko Matsakis (@nikomatsakis)</span></div></div>



<a name="175527061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175527061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175527061">(Sep 12 2019 at 13:10)</a>:</h4>
<p><span class="user-mention" data-user-id="143274">@Amanieu d'Antras</span> ^^ do you still do stuff with ARM?</p>



<a name="175527203"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175527203" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175527203">(Sep 12 2019 at 13:12)</a>:</h4>
<p>before I go AFK, let me go ahead and list the beta nomination ahead of time, to get them in peoples heads. (But without the voting emoji's; I'll put those on the messages I post during the meeting itself)</p>



<a name="175527233"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175527233" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175527233">(Sep 12 2019 at 13:12)</a>:</h4>
<p>well maybe that's silly</p>



<a name="175527267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175527267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175527267">(Sep 12 2019 at 13:13)</a>:</h4>
<p>I'll just post the link to the list for now: <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler+-label%3Abeta-accepted+" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler+-label%3Abeta-accepted+">beta-noms</a> (has three issues as of this posting)</p>



<a name="175531968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175531968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175531968">(Sep 12 2019 at 14:03)</a>:</h4>
<p>okay back again</p>



<a name="175531999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175531999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175531999">(Sep 12 2019 at 14:03)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span></p>



<a name="175532024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532024">(Sep 12 2019 at 14:03)</a>:</h4>
<p>o/</p>



<a name="175532102"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532102" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532102">(Sep 12 2019 at 14:04)</a>:</h4>
<p>I didn't <em>quite</em> make it through all the P-high issues in the parallel <a href="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-09-12.20.2354818/near/175517941" title="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-09-12.20.2354818/near/175517941">pre-triage topice</a></p>



<a name="175532138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532138">(Sep 12 2019 at 14:04)</a>:</h4>
<p>but 75% ain't too shabby</p>



<a name="175532139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532139">(Sep 12 2019 at 14:04)</a>:</h4>
<p>Nice to have you back <span class="user-mention" data-user-id="116083">@pnkfelix</span></p>



<a name="175532161"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532161" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532161">(Sep 12 2019 at 14:05)</a>:</h4>
<p>its good to be back!</p>



<a name="175532168"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532168" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532168">(Sep 12 2019 at 14:05)</a>:</h4>
<p>so lets seeeeee</p>



<a name="175532262"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532262" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532262">(Sep 12 2019 at 14:06)</a>:</h4>
<p>we have <em>twelve</em> <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+is%3Aissue+label%3AT-compiler+label%3AP-high+no%3Aassignee" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+is%3Aissue+label%3AT-compiler+label%3AP-high+no%3Aassignee">unassigned P-high</a> bugs</p>



<a name="175532360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532360">(Sep 12 2019 at 14:07)</a>:</h4>
<p>perhaps of slightly higher priority, we have <em>three</em> <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+label%3Aregression-from-stable-to-beta++label%3AT-compiler" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+label%3Aregression-from-stable-to-beta++label%3AT-compiler">beta regressions</a>; they're all currently assigned to me ...</p>



<a name="175532438"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532438" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532438">(Sep 12 2019 at 14:08)</a>:</h4>
<p>lets just make sure we review those quickly, because if I can offload two of these, it would be better all around I think</p>



<a name="175532458"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532458" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532458">(Sep 12 2019 at 14:08)</a>:</h4>
<p>1/3: "Regression: Matching on function pointers fails when one of the formal params implements custom PartialEq" <a href="https://github.com/rust-lang/rust/issues/63479" target="_blank" title="https://github.com/rust-lang/rust/issues/63479">#63479</a></p>



<a name="175532491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532491">(Sep 12 2019 at 14:08)</a>:</h4>
<p>I do think I can keep this for now; I have the custom PartialEq stuff sort of in my mental cache, somehow</p>



<a name="175532509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532509">(Sep 12 2019 at 14:09)</a>:</h4>
<p>I don't think I fully processed that this was a regression -- or at least that it might be considered urgent</p>



<a name="175532522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532522">(Sep 12 2019 at 14:09)</a>:</h4>
<p>2/3: "Segfault compiling libc on nightly-armv7-unknown-linux-gnueabihf" <a href="https://github.com/rust-lang/rust/issues/62896" target="_blank" title="https://github.com/rust-lang/rust/issues/62896">#62896</a></p>



<a name="175532566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532566">(Sep 12 2019 at 14:09)</a>:</h4>
<blockquote>
<p>I don't think I fully processed that this was a regression -- or at least that it might be considered urgent</p>
</blockquote>
<p>maybe we can double-back later and check that it deserves that prioritiation? Certainly the filer said it was a regression and it mattered to their crate, I think.</p>



<a name="175532643"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532643" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532643">(Sep 12 2019 at 14:10)</a>:</h4>
<p>regarding <a href="https://github.com/rust-lang/rust/issues/62896" target="_blank" title="https://github.com/rust-lang/rust/issues/62896">#62896</a>, I didn't really have time to digest the whole comment thread there</p>



<a name="175532656"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532656" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532656">(Sep 12 2019 at 14:10)</a>:</h4>
<p>its not clear to me what platforms are affected by this</p>



<a name="175532684"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532684" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532684">(Sep 12 2019 at 14:11)</a>:</h4>
<p>but it sounds like the claim is that the build infrastructure we are using is somehow yielding binaries that don't behave well?</p>



<a name="175532703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532703">(Sep 12 2019 at 14:11)</a>:</h4>
<p>yeah, I'm skimming it now and it's a bit confusing</p>



<a name="175532725"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532725" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532725">(Sep 12 2019 at 14:11)</a>:</h4>
<p>do we have any idea about who has been able to actually reproduce the issue?</p>



<a name="175532736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532736">(Sep 12 2019 at 14:11)</a>:</h4>
<p>is it just fenhl ?</p>



<a name="175532808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532808">(Sep 12 2019 at 14:12)</a>:</h4>
<p>and is it just ... arm hosts?</p>



<a name="175532812"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532812" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532812">(Sep 12 2019 at 14:12)</a>:</h4>
<p>maybe <span class="user-mention" data-user-id="133224">@Nikita Popov</span> ? it sounded like they saw crashes but I guess they were unrelated to root cause</p>



<a name="175532845"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532845" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532845">(Sep 12 2019 at 14:13)</a>:</h4>
<p>oconnor663 also saw issues, I wonder what platform they were on</p>



<a name="175532933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532933">(Sep 12 2019 at 14:14)</a>:</h4>
<p>okay I guess no one present feels like they could take charge on trying to reproduce locally?</p>



<a name="175532956"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532956" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532956">(Sep 12 2019 at 14:14)</a>:</h4>
<p>in which case ... I'll move along to the last bug</p>



<a name="175532965"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532965" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532965">(Sep 12 2019 at 14:14)</a>:</h4>
<p>3/3: "Undefined symbol _fltused when compiling to x86_64-unknown-uefi" <a href="https://github.com/rust-lang/rust/issues/62785" target="_blank" title="https://github.com/rust-lang/rust/issues/62785">#62785</a></p>



<a name="175532998"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175532998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175532998">(Sep 12 2019 at 14:14)</a>:</h4>
<p>this one is marked E-needs-bisection</p>



<a name="175533021"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533021" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533021">(Sep 12 2019 at 14:15)</a>:</h4>
<p>so it seems like anyone with a machine could priobably make progress</p>



<a name="175533040"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533040" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533040">(Sep 12 2019 at 14:15)</a>:</h4>
<p>both of these things raise the usual questions of "how much do we prioritize these targets"</p>



<a name="175533053"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533053" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533053">(Sep 12 2019 at 14:15)</a>:</h4>
<p>anyone willing to reboot their machine? :P</p>



<a name="175533067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533067">(Sep 12 2019 at 14:15)</a>:</h4>
<p>it feels like if we're going to prioritize bugs, we need to have an easy way to reproduce problems</p>



<a name="175533068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533068">(Sep 12 2019 at 14:16)</a>:</h4>
<p>(okay presumably you don't need to actually run the UEFI executable to get that error)</p>



<a name="175533114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533114">(Sep 12 2019 at 14:16)</a>:</h4>
<p>I had assumed target meant you could cross compile</p>



<a name="175533117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533117">(Sep 12 2019 at 14:16)</a>:</h4>
<p>but that's a topic for the meeting with <span class="user-mention" data-user-id="239881">@Josh Triplett</span>, I suppose :)</p>



<a name="175533132"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533132" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533132">(Sep 12 2019 at 14:16)</a>:</h4>
<p>yeah, if cross-compile produces the error that's good</p>



<a name="175533139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533139">(Sep 12 2019 at 14:16)</a>:</h4>
<p>so ... anyone ? Bueller?</p>



<a name="175533186"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533186" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533186">(Sep 12 2019 at 14:17)</a>:</h4>
<p>okay well I'm going to move along then</p>



<a name="175533202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533202">(Sep 12 2019 at 14:17)</a>:</h4>
<p>beta-nominations</p>



<a name="175533214"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533214" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533214">(Sep 12 2019 at 14:17)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler">https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler</a></p>



<a name="175533307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533307">(Sep 12 2019 at 14:18)</a>:</h4>
<p>beta-nom: "Update LLVM submodule" <a href="https://github.com/rust-lang/rust/issues/64317" target="_blank" title="https://github.com/rust-lang/rust/issues/64317">#64317</a></p>



<a name="175533345"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533345" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533345">(Sep 12 2019 at 14:19)</a>:</h4>
<p>so, just to play devils advocate</p>



<a name="175533360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533360">(Sep 12 2019 at 14:19)</a>:</h4>
<p>one of the riskier backports :)</p>



<a name="175533370"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533370" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533370">(Sep 12 2019 at 14:19)</a>:</h4>
<p>during the P-high review I saw a few bugs that end up blaming LLVM upgrades</p>



<a name="175533371"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533371" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533371">(Sep 12 2019 at 14:19)</a>:</h4>
<p>but also closes 2 <em>soundness holes</em></p>



<a name="175533398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Nikita Popov <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533398">(Sep 12 2019 at 14:19)</a>:</h4>
<p>Multiple people reported the issue with armv7-unknown-linux-gnueabihf, and it seems to only affect that target. Cause is unknown, apart from being due to an LLVM upgrade.</p>



<a name="175533478"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533478" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533478">(Sep 12 2019 at 14:20)</a>:</h4>
<p><span class="user-mention" data-user-id="133224">@Nikita Popov</span> i.e., possibly due to this upgrade?</p>



<a name="175533507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Nikita Popov <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533507">(Sep 12 2019 at 14:20)</a>:</h4>
<p>Due to the LLVM 9 upgrade. The beta-nom one is only backports of LLVM 9 fixes.</p>



<a name="175533539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533539">(Sep 12 2019 at 14:21)</a>:</h4>
<p>right, context: <a href="https://github.com/rust-lang/rust/issues/62896#issuecomment-515621347" target="_blank" title="https://github.com/rust-lang/rust/issues/62896#issuecomment-515621347">https://github.com/rust-lang/rust/issues/62896#issuecomment-515621347</a></p>



<a name="175533661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533661">(Sep 12 2019 at 14:22)</a>:</h4>
<blockquote>
<p>but also closes 2 <em>soundness holes</em></p>
</blockquote>
<p>sure, I'm just saying: one major point of asking these questions is to try to avoid causing even more harm with the supposed fix</p>



<a name="175533700"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533700" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533700">(Sep 12 2019 at 14:23)</a>:</h4>
<p>having said that, if this beta-nom is solely backporting fixes, then that seems pretty well focused</p>



<a name="175533726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533726">(Sep 12 2019 at 14:23)</a>:</h4>
<p>and I'm personally willing to trust the LLVM devs if they've narrowed things down in such a fashion</p>



<a name="175533728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533728">(Sep 12 2019 at 14:23)</a>:</h4>
<p>yeah, I was going to say the same</p>



<a name="175533745"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533745" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533745">(Sep 12 2019 at 14:23)</a>:</h4>
<p>okay. SOunds good. Approvided for backport then,.</p>



<a name="175533748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533748">(Sep 12 2019 at 14:23)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="175533885"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533885" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533885">(Sep 12 2019 at 14:24)</a>:</h4>
<p>beta-nom: "fix nounwind attribute logic" <a href="https://github.com/rust-lang/rust/issues/63909" target="_blank" title="https://github.com/rust-lang/rust/issues/63909">#63909</a></p>



<a name="175533987"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175533987" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175533987">(Sep 12 2019 at 14:25)</a>:</h4>
<p>hmm, which is somehow coupled with beta-nominated PR <a href="https://github.com/rust-lang/rust/issues/62603" target="_blank" title="https://github.com/rust-lang/rust/issues/62603">#62603</a>, which is assigned to T-lang?</p>



<a name="175534073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534073">(Sep 12 2019 at 14:26)</a>:</h4>
<p>Seems correct</p>



<a name="175534083"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534083" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534083">(Sep 12 2019 at 14:26)</a>:</h4>
<p>That said, I think the lang decision was to go ahead and backport (both) and push hard on reaching a better fix</p>



<a name="175534087"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534087" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534087">(Sep 12 2019 at 14:26)</a>:</h4>
<p>there's a lot of discussion</p>



<a name="175534092"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534092" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534092">(Sep 12 2019 at 14:26)</a>:</h4>
<p>But we can nominate for lang meeting if we like</p>



<a name="175534097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534097">(Sep 12 2019 at 14:26)</a>:</h4>
<p>We should at least reach a technical decision here</p>



<a name="175534108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534108">(Sep 12 2019 at 14:27)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> I changed my mind since based on the RFC discussion</p>



<a name="175534136"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534136" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534136">(Sep 12 2019 at 14:27)</a>:</h4>
<p>from a technical perspective, I think these would be <em>safe</em> to backport</p>



<a name="175534150"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534150" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534150">(Sep 12 2019 at 14:27)</a>:</h4>
<p>(which I guess is the major decision we need to make here?)</p>



<a name="175534210"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534210" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534210">(Sep 12 2019 at 14:28)</a>:</h4>
<p>is the PR sufficiently tested?</p>



<a name="175534247"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534247" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534247">(Sep 12 2019 at 14:29)</a>:</h4>
<p>I am still playing catch up here; I cannot immediate tell from the description alone what change is <strong>implemented</strong> by PR <a href="https://github.com/rust-lang/rust/issues/63909" target="_blank" title="https://github.com/rust-lang/rust/issues/63909">#63909</a>.</p>



<a name="175534275"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534275" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534275">(Sep 12 2019 at 14:29)</a>:</h4>
<p>Is it that it removes an implicitly injected <code>nounwind</code> for <code>extern fn</code> ?</p>



<a name="175534360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534360">(Sep 12 2019 at 14:30)</a>:</h4>
<p>and ... what beta regression, if any, is this fixing?</p>



<a name="175534385"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534385" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534385">(Sep 12 2019 at 14:30)</a>:</h4>
<p>it's not fixing a beta regression</p>



<a name="175534392"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534392" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534392">(Sep 12 2019 at 14:30)</a>:</h4>
<p>and ... if it hasn't landed on nightly, we certainly can't backport it</p>



<a name="175534394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534394">(Sep 12 2019 at 14:30)</a>:</h4>
<p>right?</p>



<a name="175534401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534401">(Sep 12 2019 at 14:30)</a>:</h4>
<blockquote>
<p>Is it that it removes an implicitly injected <code>nounwind</code> for <code>extern fn</code> ?</p>
</blockquote>
<p>correct</p>



<a name="175534411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534411">(Sep 12 2019 at 14:30)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> my thoughts exactly re. not having landed on nightly</p>



<a name="175534414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534414">(Sep 12 2019 at 14:30)</a>:</h4>
<blockquote>
<p>and ... what beta regression, if any, is this fixing?</p>
</blockquote>
<p>it's not fixing a beta regression exactly</p>



<a name="175534430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534430">(Sep 12 2019 at 14:30)</a>:</h4>
<p>(i.e. this might not even be the final state of the PR)</p>



<a name="175534597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534597">(Sep 12 2019 at 14:32)</a>:</h4>
<p>I think my inclination, based on what I've seen, would be to decline beta-acceptance of this <em>for now</em>, but invite people to re-nominate it after it has landed in nightly ...?</p>



<a name="175534629"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534629" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534629">(Sep 12 2019 at 14:32)</a>:</h4>
<p>but I say this while also saying that I am <em>really</em> out of the loop here</p>



<a name="175534636"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534636" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534636">(Sep 12 2019 at 14:33)</a>:</h4>
<p>sounds good (...assuming it will land on nightly, which isn't clear it will do)</p>



<a name="175534642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534642">(Sep 12 2019 at 14:33)</a>:</h4>
<p>What happens is this:</p>
<ul>
<li><a href="https://github.com/rust-lang/rust/issues/62603" target="_blank" title="https://github.com/rust-lang/rust/issues/62603">#62603</a> prevents us from aborting on existing libraries due to inserting shims; but, on its own, it leaves LLVM UB (as indeed they have had for quite some time)</li>
<li><a href="https://github.com/rust-lang/rust/issues/63909" target="_blank" title="https://github.com/rust-lang/rust/issues/63909">#63909</a> goes further and makes those cases not UB</li>
</ul>
<p>the discussion we had in the lang team was basically about how to handle this. At the time, there was a (loose, I would say) agreement that:</p>
<ul>
<li>we should come up with a real fix and stop backporting temporary hacks</li>
<li>but in the meantime, we might as well be internally consistent</li>
</ul>
<p>That said, I don't have a strong opinion about this, except that I definitely think we should get out story in order and stop revisiting this question. I kind of think it's ok to live in ambiguity for the time being though, it's been that way a long time.</p>



<a name="175534682"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534682">(Sep 12 2019 at 14:33)</a>:</h4>
<p>okay, sure. But <a href="https://github.com/rust-lang/rust/issues/62603" target="_blank" title="https://github.com/rust-lang/rust/issues/62603">#62603</a> hasn't been approved for backport yet anyway</p>



<a name="175534695"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534695" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534695">(Sep 12 2019 at 14:33)</a>:</h4>
<p>anyway, I think it's ok to decline to beta nominate, as long as we're clear on the reason ("not on nightly")</p>



<a name="175534704"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534704" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534704">(Sep 12 2019 at 14:33)</a>:</h4>
<p>so that's another approach, is to punt the decision here until that <a href="https://github.com/rust-lang/rust/issues/62603" target="_blank" title="https://github.com/rust-lang/rust/issues/62603">#62603</a> decision has been made.</p>



<a name="175534840"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534840" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534840">(Sep 12 2019 at 14:35)</a>:</h4>
<p>in the interest of time, let's move on to something else?</p>



<a name="175534844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534844">(Sep 12 2019 at 14:35)</a>:</h4>
<p>I say we punt for now and revisit.</p>



<a name="175534860"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534860" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534860">(Sep 12 2019 at 14:35)</a>:</h4>
<p>(where that can be 62603)</p>



<a name="175534956"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534956" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534956">(Sep 12 2019 at 14:36)</a>:</h4>
<p>okay, so ...</p>



<a name="175534989"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175534989" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175534989">(Sep 12 2019 at 14:36)</a>:</h4>
<p>last beta-nom: "pprust: Do not print spaces before some tokens" <a href="https://github.com/rust-lang/rust/issues/63897" target="_blank" title="https://github.com/rust-lang/rust/issues/63897">#63897</a></p>



<a name="175535031"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535031" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535031">(Sep 12 2019 at 14:37)</a>:</h4>
<p>feels safe</p>



<a name="175535077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535077">(Sep 12 2019 at 14:37)</a>:</h4>
<p>yeah I agree</p>



<a name="175535102"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535102" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535102">(Sep 12 2019 at 14:37)</a>:</h4>
<p>sort of weird it was causing assert fails</p>



<a name="175535127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535127">(Sep 12 2019 at 14:37)</a>:</h4>
<p>but I guess I can understand</p>



<a name="175535130"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535130" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535130">(Sep 12 2019 at 14:37)</a>:</h4>
<p>in terms of the legacy code involved here</p>



<a name="175535200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535200">(Sep 12 2019 at 14:38)</a>:</h4>
<p>tho I'm wondering why the PR uses two nested <code>match</code>es... (not important re. beta backport... more a stylistic thing)</p>



<a name="175535250"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535250" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535250">(Sep 12 2019 at 14:38)</a>:</h4>
<p>(and that comment could be made into a doc comment -- strictly C-enhancement tho)</p>



<a name="175535289"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535289" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535289">(Sep 12 2019 at 14:39)</a>:</h4>
<p>okay so</p>



<a name="175535324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535324">(Sep 12 2019 at 14:39)</a>:</h4>
<p>no stable nominations, good</p>



<a name="175535382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535382">(Sep 12 2019 at 14:40)</a>:</h4>
<p>(Also unnominating for lang team)</p>



<a name="175535430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535430">(Sep 12 2019 at 14:40)</a>:</h4>
<p>so there are four <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+label%3AI-nominated+label%3AT-compiler" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=is%3Aopen+label%3AI-nominated+label%3AT-compiler">I-nominated</a></p>



<a name="175535443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535443">(Sep 12 2019 at 14:40)</a>:</h4>
<p>but only 20 minutes left</p>



<a name="175535464"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535464" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535464">(Sep 12 2019 at 14:40)</a>:</h4>
<p>there was the one that <span class="user-mention" data-user-id="124287">@mw</span> wanted us to talk about</p>



<a name="175535467"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535467" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535467">(Sep 12 2019 at 14:40)</a>:</h4>
<p>(see <a href="#narrow/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818/near/175523249" title="#narrow/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818/near/175523249">start</a> of topic)</p>



<a name="175535492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535492">(Sep 12 2019 at 14:41)</a>:</h4>
<p>I-nominated: "Make the generator-locals debuginfo test resilient to re-ordering." <a href="https://github.com/rust-lang/rust/issues/63742" target="_blank" title="https://github.com/rust-lang/rust/issues/63742">#63742</a></p>



<a name="175535724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535724">(Sep 12 2019 at 14:43)</a>:</h4>
<p>well if nothing else, it seems like the people working on generators and such have been alerted to an issue here</p>



<a name="175535738"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535738" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535738">(Sep 12 2019 at 14:43)</a>:</h4>
<p>so maybe we can let that slide</p>



<a name="175535776"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535776" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535776">(Sep 12 2019 at 14:43)</a>:</h4>
<p>and I'd rather focus on the WG check-in</p>



<a name="175535791"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535791" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535791">(Sep 12 2019 at 14:43)</a>:</h4>
<p>rather than the other three nominated issues right now</p>



<a name="175535875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535875">(Sep 12 2019 at 14:44)</a>:</h4>
<p>(and also my son is attempting to type on my keyboard, so its a good time for me to hand off the controls)</p>



<a name="175535903"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535903" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535903">(Sep 12 2019 at 14:44)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> you want to tell us what's up with Polonius and RFC 2229?</p>



<a name="175535926"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535926" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535926">(Sep 12 2019 at 14:44)</a>:</h4>
<p>Sure--</p>



<a name="175535951"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535951" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535951">(Sep 12 2019 at 14:45)</a>:</h4>
<h1>Polonius WG checking</h1>
<p>cc <span class="user-group-mention" data-user-group-id="1184">@WG-polonius</span></p>



<a name="175535960"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535960" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535960">(Sep 12 2019 at 14:45)</a>:</h4>
<p>We are "rebooting" after a long hiatus. In general, our focus at present is on expanding the Polonius coverage so that it includes not just the "core" of borrow check but also things like the initialization checks and more of region subtyping.</p>



<a name="175535985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175535985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175535985">(Sep 12 2019 at 14:45)</a>:</h4>
<p>We've made some progress on the code there, but we also decided to step back and start writing a polonius book that helps to document the rules. This is partly because it's hard to review the code in isolation, it'd be nice to be able to read the book first as a kind of spec and then compare to the code. But it will also make the system better documented and make it easier for people to get involved.</p>



<a name="175536006"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536006" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536006">(Sep 12 2019 at 14:45)</a>:</h4>
<p>On a related note, <span class="user-mention" data-user-id="204115">@Albin Stjerna</span> has been working on their master's thesis, which includes a lot of great coverage.</p>



<a name="175536015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536015">(Sep 12 2019 at 14:45)</a>:</h4>
<p>Other areas of effort worth noting:</p>



<a name="175536121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536121">(Sep 12 2019 at 14:46)</a>:</h4>
<ul>
<li>in talking things over with <span class="user-mention" data-user-id="127262">@Aaron Weiss</span>, we found that there may be opportunities to make the polonius rules more precise, which we are also exploring.  There's a <a href="https://www.youtube.com/watch?v=mAUGvNgZYtw&amp;list=PL85XCvVPmGQitE2CBzf-gERSqeXo59NQG&amp;index=4&amp;t=0s" target="_blank" title="https://www.youtube.com/watch?v=mAUGvNgZYtw&amp;list=PL85XCvVPmGQitE2CBzf-gERSqeXo59NQG&amp;index=4&amp;t=0s">youtube video</a> where we talked about it.</li>
</ul>
<div class="youtube-video message_inline_image"><a data-id="mAUGvNgZYtw" href="https://www.youtube.com/watch?v=mAUGvNgZYtw&amp;list=PL85XCvVPmGQitE2CBzf-gERSqeXo59NQG&amp;index=4&amp;t=0s" target="_blank" title="https://www.youtube.com/watch?v=mAUGvNgZYtw&amp;list=PL85XCvVPmGQitE2CBzf-gERSqeXo59NQG&amp;index=4&amp;t=0s"><img src="https://i.ytimg.com/vi/mAUGvNgZYtw/default.jpg"></a></div>



<a name="175536144"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536144" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536144">(Sep 12 2019 at 14:47)</a>:</h4>
<ul>
<li><span class="user-mention" data-user-id="204115">@Albin Stjerna</span> landed the code so that we do all the liveness computation in Polonius. We also do some amount of initialization computation, but only enough to decide if a DROP in MIR is a no-op (because the value being dropped has been moved). This is the work we are aiming to document now.</li>
</ul>



<a name="175536170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536170">(Sep 12 2019 at 14:47)</a>:</h4>
<ul>
<li><span class="user-mention" data-user-id="116113">@lqd</span> has been making great strides on getting a "polonius compare-mode" ready to go. We basically pass all tests now, I think (building on some cleanups and efforts by <span class="user-mention" data-user-id="116118">@Matthew Jasper</span>, iirc)</li>
</ul>



<a name="175536184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536184">(Sep 12 2019 at 14:47)</a>:</h4>
<ul>
<li>we've also done some performance analysis. In particular we found some OOM cases we need to look at, although I believe the suspicion is that they are related to giant constants (which rustc presently special cases).</li>
</ul>



<a name="175536250"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536250" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536250">(Sep 12 2019 at 14:48)</a>:</h4>
<p>one of the things we decided in our last meeting was that we need to settle also our vocabulary :)</p>



<a name="175536279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536279">(Sep 12 2019 at 14:48)</a>:</h4>
<p>provs / lifetimes / regions ... ?</p>



<a name="175536300"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536300" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536300">(Sep 12 2019 at 14:48)</a>:</h4>
<p>we've got some burning issues, like what to call <em>region</em> ... (leading candidates are <em>origin</em> or <em>provenance</em>, I believe)</p>



<a name="175536327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536327">(Sep 12 2019 at 14:48)</a>:</h4>
<p>but anyway we expect to iron that out as part of the book chapter reviews, then bring code in sync</p>



<a name="175536335"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536335" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536335">(Sep 12 2019 at 14:48)</a>:</h4>
<blockquote>
<ul>
<li>we've also done some performance analysis. In particular we found some OOM cases we need to look at, although I believe the suspicion is that they are related to giant constants (which rustc presently special cases).</li>
</ul>
</blockquote>
<p>any chance this might be handled via .. i dunno, some sort of change in representation?</p>



<a name="175536353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536353">(Sep 12 2019 at 14:49)</a>:</h4>
<p>(the idea being:</p>
<ul>
<li>a <em>loan</em> creates a reference (i.e., <code>&amp;foo</code>)</li>
<li>the reference has an associated <em>origin</em> (or <em>provenance</em>) which is a set of loans that may have created it</li>
</ul>



<a name="175536404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536404">(Sep 12 2019 at 14:50)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> not sure, I've not really looked at where the error is coming from, but I would guess that it'd be handled by some more optimized variant of the rules that avoids creating tuples for some cases</p>



<a name="175536505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536505">(Sep 12 2019 at 14:50)</a>:</h4>
<p>Relatedly: NLL errors that AST borrowck accepts are no longer downgraded to warnings on Rust 2018 as of 1.39.</p>



<a name="175536524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536524">(Sep 12 2019 at 14:51)</a>:</h4>
<p>In 1.40 we push this to Rust 2015 as well.</p>



<a name="175536539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536539">(Sep 12 2019 at 14:51)</a>:</h4>
<p>(and then we can throw out AST borrowck)</p>



<a name="175536572"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536572" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536572">(Sep 12 2019 at 14:51)</a>:</h4>
<p>OK, so, RFC 2229 now?</p>



<a name="175536581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536581">(Sep 12 2019 at 14:51)</a>:</h4>
<h1>RFC 2229</h1>
<p>cc <span class="user-group-mention" data-user-group-id="1175">@WG-rfc-2229</span></p>



<a name="175536586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536586">(Sep 12 2019 at 14:51)</a>:</h4>
<p>Less to report there</p>



<a name="175536601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536601">(Sep 12 2019 at 14:52)</a>:</h4>
<p>We've basiaclly been stalled at the same spot for a while</p>



<a name="175536653"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536653" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536653">(Sep 12 2019 at 14:52)</a>:</h4>
<p><span class="user-mention" data-user-id="128294">@blitzerr</span> was doing this refactoring to change how closure substitutions work so that the number of type parameters is independent of the number of captured variables</p>



<a name="175536657"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536657" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536657">(Sep 12 2019 at 14:52)</a>:</h4>
<p>This is basically done but</p>



<a name="175536665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536665">(Sep 12 2019 at 14:52)</a>:</h4>
<p>It led to some minor regressions in the diagnostic output</p>



<a name="175536669"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536669" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536669">(Sep 12 2019 at 14:52)</a>:</h4>
<p>Moreover, the compiler has changed a lot in the meantime</p>



<a name="175536671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536671">(Sep 12 2019 at 14:52)</a>:</h4>
<p>So it needs to be rebased</p>



<a name="175536674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536674">(Sep 12 2019 at 14:52)</a>:</h4>
<p>We <em>were</em> trying to fix those regressions -- basically there's an added tuple in there --</p>



<a name="175536686"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536686" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536686">(Sep 12 2019 at 14:53)</a>:</h4>
<p>but it's been kind of annoying to make it go away</p>



<a name="175536699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536699">(Sep 12 2019 at 14:53)</a>:</h4>
<p>it probably just needs a few hours of concentrated time, but those have been hard to come by</p>



<a name="175536712"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536712" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536712">(Sep 12 2019 at 14:53)</a>:</h4>
<p>To help everyone remember...</p>



<a name="175536729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536729">(Sep 12 2019 at 14:53)</a>:</h4>
<p>RFC 2229 is the work to change it so that closures don't capture entire variables, but rather subpaths</p>



<a name="175536748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536748">(Sep 12 2019 at 14:53)</a>:</h4>
<p>is <span class="user-mention" data-user-id="128294">@blitzerr</span> still  actively working on this, or are you trying to revive their work?</p>



<a name="175536770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536770">(Sep 12 2019 at 14:54)</a>:</h4>
<p>They're still around, they were busy for a while</p>



<a name="175536828"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536828" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536828">(Sep 12 2019 at 14:54)</a>:</h4>
<p>Every once in a while I carve out some time to look at it again and makes some suggestions</p>



<a name="175536842"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536842" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536842">(Sep 12 2019 at 14:54)</a>:</h4>
<p>but my last round of tips didn't work out :) which is why we still have a few tests failing</p>



<a name="175536851"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536851" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536851">(Sep 12 2019 at 14:54)</a>:</h4>
<p>I think at this point, I'm leaning towards, let's just rebase and fix the problem afresh on master</p>



<a name="175536863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536863">(Sep 12 2019 at 14:54)</a>:</h4>
<p>it's sort of an "off by one" sort of thing</p>



<a name="175536894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536894">(Sep 12 2019 at 14:55)</a>:</h4>
<p>i.e., we have some chain of types, and we need to suppress "just the right one" from the diagnostic output, but for some reason that's been surprisingly annoying :)</p>



<a name="175536913"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536913" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536913">(Sep 12 2019 at 14:55)</a>:</h4>
<p>Is there any low hanging fruit one could make mentoring issues for?</p>



<a name="175536937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536937">(Sep 12 2019 at 14:55)</a>:</h4>
<p>sort of yes</p>



<a name="175536942"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536942" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536942">(Sep 12 2019 at 14:55)</a>:</h4>
<p>this kind of <em>is</em> that</p>



<a name="175536999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175536999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175536999">(Sep 12 2019 at 14:56)</a>:</h4>
<p>that said, there are some other issues that need some refreshed mentoring instructions, since again the compiler changed out from under them</p>



<a name="175537030"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537030" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537030">(Sep 12 2019 at 14:56)</a>:</h4>
<blockquote>
<p>this kind of <em>is</em> that</p>
</blockquote>
<p>that is, this <em>is</em> the low hanging fruit, we're following a chain of refactoring steps I wrote out some time back and added mentoring instructions for, and this is the next step</p>



<a name="175537050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537050">(Sep 12 2019 at 14:56)</a>:</h4>
<p>but it would be good to go back over those steps again and refresh them</p>



<a name="175537113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537113">(Sep 12 2019 at 14:57)</a>:</h4>
<p>that's all I got :)</p>



<a name="175537124"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537124" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537124">(Sep 12 2019 at 14:57)</a>:</h4>
<p>okay</p>



<a name="175537128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537128">(Sep 12 2019 at 14:57)</a>:</h4>
<p>three minutes leeft</p>



<a name="175537137"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537137" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537137">(Sep 12 2019 at 14:57)</a>:</h4>
<p>I want to just point people at one of the other nominated issues</p>



<a name="175537200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537200">(Sep 12 2019 at 14:58)</a>:</h4>
<p><span aria-label="exclamation" class="emoji emoji-2757" role="img" title="exclamation">:exclamation:</span> I-nominated: "rustc_target: use Integer instead of Primitive for discriminants and niches." <a href="https://github.com/rust-lang/rust/issues/63450" target="_blank" title="https://github.com/rust-lang/rust/issues/63450">#63450</a></p>



<a name="175537228"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537228" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537228">(Sep 12 2019 at 14:58)</a>:</h4>
<p>any situation  where <span class="user-mention" data-user-id="119009">@eddyb</span> wants to <a href="https://github.com/rust-lang/rust/pull/63450#issuecomment-523385921" target="_blank" title="https://github.com/rust-lang/rust/pull/63450#issuecomment-523385921">ask</a> what the right answer is</p>



<a name="175537251"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537251" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537251">(Sep 12 2019 at 14:58)</a>:</h4>
<p>(versus figuring it out for themself, or "just knowing"</p>



<a name="175537265"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537265" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537265">(Sep 12 2019 at 14:59)</a>:</h4>
<p>seems like a case worth at least pointing out to the group</p>



<a name="175537272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537272">(Sep 12 2019 at 14:59)</a>:</h4>
<p><span aria-label="smiley" class="emoji emoji-1f603" role="img" title="smiley">:smiley:</span></p>



<a name="175537323"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537323" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537323">(Sep 12 2019 at 14:59)</a>:</h4>
<p>if I "just knew" what the perfect compiler looked like, I wouldn't contribute to rustc :P</p>



<a name="175537379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537379">(Sep 12 2019 at 15:00)</a>:</h4>
<p>right: You'd fork it!</p>



<a name="175537413"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537413" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537413">(Sep 12 2019 at 15:00)</a>:</h4>
<p>more seriously, that one is annoying because it's sort of a tradeoff</p>



<a name="175537415"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537415" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537415">(Sep 12 2019 at 15:00)</a>:</h4>
<p>seems like a good design meeting issue</p>



<a name="175537416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537416">(Sep 12 2019 at 15:00)</a>:</h4>
<p>anyway, we don't actually have time to do the discussion synchronously in this time slot</p>



<a name="175537419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537419">(Sep 12 2019 at 15:00)</a>:</h4>
<p>just sayin'</p>



<a name="175537425"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537425" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537425">(Sep 12 2019 at 15:00)</a>:</h4>
<p>but  Iwanted to point it out</p>



<a name="175537438"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537438" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537438">(Sep 12 2019 at 15:00)</a>:</h4>
<p>it wasn't <em>supposed to</em> (be a tradeoff) but signed integers make life hard for everyone</p>



<a name="175537440"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537440" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537440">(Sep 12 2019 at 15:00)</a>:</h4>
<p>(though maybe overkill:)</p>



<a name="175537449"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537449" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537449">(Sep 12 2019 at 15:00)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> you think its worth a design meeting slot? maybe</p>



<a name="175537465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537465">(Sep 12 2019 at 15:01)</a>:</h4>
<p>I mean I don't see why not</p>



<a name="175537472"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537472" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537472">(Sep 12 2019 at 15:01)</a>:</h4>
<p>i guess it would be a good use of that time slot, maybe batch together some of these nominations like this</p>



<a name="175537497"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537497" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537497">(Sep 12 2019 at 15:01)</a>:</h4>
<p>even better if you can invite <span class="user-mention" data-user-id="120791">@RalfJ</span></p>



<a name="175537498"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537498" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537498">(Sep 12 2019 at 15:01)</a>:</h4>
<p>it's waited 22 days for attention here</p>



<a name="175537499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537499">(Sep 12 2019 at 15:01)</a>:</h4>
<p>anyway, thanks to everyone in <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span> for attending!!!</p>



<a name="175537509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537509">(Sep 12 2019 at 15:01)</a>:</h4>
<p>the point of that slot was to have a space for deeper technical discussions</p>



<a name="175537528"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537528" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537528">(Sep 12 2019 at 15:01)</a>:</h4>
<p>I don't think it has to be a whole compiler refactoring to qualify, personally</p>



<a name="175537541"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537541" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537541">(Sep 12 2019 at 15:01)</a>:</h4>
<blockquote>
<p>it's waited 22 days for attention here</p>
</blockquote>
<p>wish I could take the blame for that, but <em>for once</em>, it wasn't me!</p>



<a name="175537609"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537609" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537609">(Sep 12 2019 at 15:02)</a>:</h4>
<p>Oh I can find a way to blame you, if you want</p>



<a name="175537649"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537649" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537649">(Sep 12 2019 at 15:02)</a>:</h4>
<p>/me points at his children, and French's childcare system</p>



<a name="175537684"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537684" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537684">(Sep 12 2019 at 15:03)</a>:</h4>
<p>speaking of which... I'm outta here! See you all later.</p>



<a name="175537698"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537698" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537698">(Sep 12 2019 at 15:03)</a>:</h4>
<p>( BTW, <span class="user-mention" data-user-id="125250">@Wesley Wiser</span>, are you going to make minutes here? )</p>



<a name="175537707"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537707" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537707">(Sep 12 2019 at 15:03)</a>:</h4>
<p>This reminds me that</p>



<a name="175537726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537726">(Sep 12 2019 at 15:03)</a>:</h4>
<p>we are thinking of creating a "team blog" -- we could start posting working group updates and select notes from triage there</p>



<a name="175537731"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537731" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537731">(Sep 12 2019 at 15:03)</a>:</h4>
<p>Yes, I'll probably have a PR up in a few hours.</p>



<a name="175537783"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537783" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537783">(Sep 12 2019 at 15:04)</a>:</h4>
<p>awesome</p>



<a name="175537798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537798">(Sep 12 2019 at 15:04)</a>:</h4>
<p>you rock</p>



<a name="175537831"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537831" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537831">(Sep 12 2019 at 15:04)</a>:</h4>
<p>btw, <span class="user-mention" data-user-id="116083">@pnkfelix</span>  if you can take a look at <a href="https://github.com/rust-lang/rust/pull/63770" target="_blank" title="https://github.com/rust-lang/rust/pull/63770">https://github.com/rust-lang/rust/pull/63770</a> for a sec that'd be nice</p>



<a name="175537910"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175537910" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175537910">(Sep 12 2019 at 15:05)</a>:</h4>
<p>/me will go through the rfcbot list later; has to go AFK. only had time for a single final <span aria-label="rock on" class="emoji emoji-1f918" role="img" title="rock on">:rock_on:</span></p>



<a name="175538000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175538000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175538000">(Sep 12 2019 at 15:06)</a>:</h4>
<blockquote>
<p>/me points at his children, and French's childcare system</p>
</blockquote>
<p><em>notes down: "don't have kids, never get sick"</em></p>



<a name="175538038"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175538038" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175538038">(Sep 12 2019 at 15:06)</a>:</h4>
<p>(I misread the latter as "healthcare" but still applies)</p>



<a name="175538042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175538042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175538042">(Sep 12 2019 at 15:07)</a>:</h4>
<p>At least there is a childcare system ;)</p>



<a name="175538791"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175538791" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175538791">(Sep 12 2019 at 15:14)</a>:</h4>
<p>I CCed a colleague who might be able to help.</p>



<a name="175539015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175539015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175539015">(Sep 12 2019 at 15:16)</a>:</h4>
<blockquote>
<p><a href="https://github.com/rust-lang/rust/issues/63909" target="_blank" title="https://github.com/rust-lang/rust/issues/63909">#63909</a> goes further and makes those cases not UB</p>
</blockquote>
<p>nitpick: those cases are still UB, that PR just removes an attribute that might cause LLVM to "optimize" them.</p>



<a name="175539272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175539272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175539272">(Sep 12 2019 at 15:19)</a>:</h4>
<p>(Help with the uefi target, I mean.)</p>



<a name="175799160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-09-12%20%2354818/near/175799160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-09-12.20.2354818.html#175799160">(Sep 16 2019 at 10:09)</a>:</h4>
<p>(I moved much followup discussion of <a href="https://github.com/rust-lang/rust/issues/63450" target="_blank" title="https://github.com/rust-lang/rust/issues/63450">#63450</a> over  to here: <a href="#narrow/stream/131828-t-compiler/topic/.2363450.20tracking.20discriminant.20type.2C.20Primitive.20vs.20Integer.2Bs.2E.2E.2E/near/175797635" title="#narrow/stream/131828-t-compiler/topic/.2363450.20tracking.20discriminant.20type.2C.20Primitive.20vs.20Integer.2Bs.2E.2E.2E/near/175797635">https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.2363450.20tracking.20discriminant.20type.2C.20Primitive.20vs.20Integer.2Bs.2E.2E.2E/near/175797635</a> )</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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